Electronic commerce, such as online shopping, has been increasingly common since the advent of the Internet. Merchants may develop and maintain an online shopping website that provides a user interface for customers to select products to purchase, and then have their orders processed directly by the merchant or a third party intermediary. However, the user must navigate to the merchant's online shopping website to search for and ultimately purchase the product.
Product comparison websites have been developed to direct users to the merchant's online shopping website. The product comparison websites provide the user with an interface comprising form fields into which the user can type a product query. The product comparison website executes the query and returns a list of merchants selling that particular product, as well as pricing information. The user can click on a product displayed in the list and is directed to the merchant's website.
Merchants elect to be included in by the product comparison website by submitting offer feeds for one or more products. However, spam merchants exist that upload malicious or fraudulent offer feeds with the intent of getting undeserved user traffic. A spam merchant may require that the user has to click through useless intermediate spam pages to get to the real product page. The user may purchase counterfeit merchandise or illegal drugs from unlicensed pharmacies. Alternatively, the spam merchant may send the wrong product, no product at all, or they may steal the user's credit card information.
Once a spam merchant is identified, it is removed from the product comparison website query. However, spam merchants tend to reopen a new account with the product comparison website after changing their website address, the appearance of their site, or making other minor changes to the offer feed submitted.